1. Technical Field
The inventive concepts relate generally to semiconductor memory devices, and more particularly to nonvolatile memory devices, methods of operating nonvolatile memory devices and solid state drives including the same.
2. Discussion of the Related Art
Semiconductor memory devices may be classified as volatile semiconductor memory devices or nonvolatile semiconductor memory devices. Volatile semiconductor memory devices may perform read and write operations at high speed, while contents stored therein may be lost when the devices are powered-off. Nonvolatile semiconductor memory devices may retain contents stored therein even when powered-off. For this reason, nonvolatile semiconductor memory devices may be used to store contents that need to be retained regardless of whether the devices are powered on or off.
Nonvolatile semiconductor memory devices may include devices, such as mask read-only memories (MROMs), programmable ROMs (PROMs), erasable programmable ROMs (EPROMs), electrically erasable programmable ROMs (EEPROMs), etc.
A flash memory device is a type of nonvolatile memory device. Flash memory devices are widely used to store media on electronic apparatuses such as computers, cellular phones, PDAs, digital cameras, camcorders, voice recorders, MP3 players, handheld PCs, game machines, facsimiles, scanners, printers, etc.
As the demands for increased storage capability have increase, manufacturers of memory devices have sought to increase the integration level of semiconductor memories. To that end, multi-bit memory devices that store multiple bits of data in each memory cell have been developed.